1. Field of the Invention
The present invention relates to a grinding tool which is inserted to a round hole provided in a subject to be worked while rotating so as to grind the inner surface of the round hole, for the purpose of adjusting the inner diameter of the round hole or the like.
2. Prior Art
As this kind of grinding tool, a grinding tool in which a part in the axial direction of the tool is structured such as to be expandable and the outer diameter of the tool can be adjusted very precisely and simply due to such expansion has been described in Japanese Utility Model Registration gazette No. 3005414. A structure of the conventional grinding tool is shown in FIG. 4.
The grinding tool is constituted by a tool main body 1 in which a front end portion is formed in a cylindrical shape, and an expanding member 3 which is press-fitted within a cylinder portion 2 of the tool main body 1 so as to expand the cylinder portion 2. Abrasive grains such as diamond powders or the like are adhered to the outer surface of the cylinder portion 2 in the tool main body 1 so as to form a grinding portion. The inner surface of the cylinder portion 2 forms a taper surface in which the inner diameter gradually reduces toward a rear end. A slit 4 in the axial direction is provided at a plurality of positions in a circumferential direction of the cylinder portion 2 except a front end portion and a base end portion. The expanding member 3 has an expanding head 5 which is press-fitted within the grinding portion, and a bolt 6 which is screwed to a depth surface of the cylinder portion 2 for said press-fitting.
The grinding portion of the tool main body 1 can be expanded by a plurality of slits 4, and the outer diameter thereof is adjusted very precisely and simply on the basis of a movement in the axial direction of the expanding head 5 caused by screwing the bolt 6. Furthermore, in order to smoothly perform work, the outer diameter of the grinding portion is made slightly larger than the outer diameter of the other portions.
Issues to be Solved by the Invention
The grinding tool shown in FIG. 4 can grind to a high inner diameter precision the inner surface of the round hole provided in a subject material to be worked by fine adjustments of the outer diameter of the grinding portion.
Generally, however, the process using the conventional grinding tool, including this grinding tool, requires processing the round hole by grinding reamer 8 in the subject to be worked 7 before inner surface grinding by the grinding tool, as shown in FIG. 5(a). Furthermore, after the inner surface of the round hole is ground, the inner surface is generally brushed by brush 9 to remove grinding particles, as shown in FIG. 5(b).
In other words, even the high precision grinding tool shown in FIG. 4 requires as does the common grinding tool the three processes of creating the hole, grinding the inner surface, and brushing the inner surface in order to perform the process as a series, including inner surface grinding, and hence it has not been possible to reduce processing man-hours and processing time.
The present invention is made by taking the matters mentioned above into consideration, and an object of the present invention is to provide a highly efficient grinding tool which can reduce processing man-hours and processing time required to process the series, including inner surface grinding.
Method of Solving the Issues
In order to achieve the object mentioned above, in accordance with the present invention, there is provided a grinding tool inserted to a hole provided in a subject to be worked while rotating so as to grind the inner surface of the hole, comprising: a tool main body in which abrasive grains such as diamond powders or the like are adhered to at least a part of the outer surface in the axial portion, and that portion serves as the grinding portion, and a working member in which a working portion is provided in the front portion to perform working processes before or after grinding of the inner surface in the subject to be worked and a rear portion that is combined to the tool main body be able to be attached thereto and removed therefrom in such a way as to maintain the working portion to the front end side of the tool main body.
The working member given here has, for example, a grinding reamer or a rotating brush. By the installation of the grinding reamer as a working member in the front end portion of the tool main body and upon processing the hole by the grinding reamer, the grinding process of the inner surface can be done by the grinding portion of the tool main body in a continuous maimer. Furthermore, by the installation of the rotating brush, upon the grinding process of the inner surface by the grinding portion of the tool main body, the brushing of the inner surface can be done in a continuous manner.
As for the tool main body, it is preferred that at least the front end portion in the axial direction is formed in a cylindrical shape, slits in the axial direction are provided in a part in the axial direction of the cylinder portion at a predetermined interval in a circumferential direction, abrasive grains such as diamond powders or the like are adhered to the outer surface thereof so as to form an expandable grinding portion in part of the axial portion, and an expanding member press-fitted within the grinding portion to expand the grinding portion, thereby adjusting the outer diameter of the grinding portion.
The advantages of the tool main body are not only that it is capable of adjusting the outer diameter of the grinding portion with high accuracy by moving the expanding member in the axial direction, but also because the front end portion is formed as a cylinder, using the cylindrical part it can be combined in a simple fitting mechanism including screwing the working member in the main body front end.
For example, providing a female screw portion in the inner surface of the front end portion of the cylindrical portion of the tool main body, the male screw portion to be screwed into the female screw portion is provided in the outer surface of the back portion of the working member, and with the working portion provided to the front portion of the working member, the working member can be easily combined to or removed from the front end portion of the tool main body by screwing.
Furthermore, by matching the screwing of this working tool, the male screw portion to be screwed into the female screw portion of the tool main body is provided in the outer surface of the front portion of the expanding member, and with the expanding head to be press-fitted in the grinding portion of the tool main body provided in the rear portion of the expanding member, the movement of the expanding portion in the axial direction can be performed with a simple mechanism using the male screw portion of the tool main body.
The tool main body is preferably structured such that the inner surface of the grinding portion is constituted by a taper surface which has a diameter which is gradually reduced toward the rear end side, and the grinding portion is expanded on the basis of the movement of the expanding head press-fitted within the grinding portion in the axial direction. In accordance with this structure, it is possible to simplify the expanding mechanism.